[PATCH -mm 10/14] bootmem: factor out the marking of a PFN range

Johannes Weiner
2008-06-03T02:01:32Z

[-- Attachment #1: bootmem-refactor-range-marking.patch --]
[-- Type: text/plain, Size: 8803 bytes --]

Introduce new helpers that mark a range that resides completely on a
node or node-agnostic ranges that might also span node boundaries.

The free/reserve API functions will then directly use these helpers.

Note that the free/reserve semantics become more strict: while the
prior code took basically arbitrary range arguments and marked the
PFNs that happen to fall into that range, the new code requires
node-specific ranges to be completely on the node. The node-agnostic
requests might span node boundaries as long as the nodes are
contiguous.

Passing ranges that do not satisfy these criteria is a bug.

Signed-off-by: Johannes Weiner <hannes@saeurebad.de>
CC: Ingo Molnar <mingo@elte.hu>
CC: Yinghai Lu <yhlu.kernel@gmail.com>
CC: Andi Kleen <andi@firstfloor.org>
---

include/linux/bootmem.h | 2
mm/bootmem.c | 189 +++++++++++++++++-------------------------------
2 files changed, 71 insertions(+), 120 deletions(-)

--- a/mm/bootmem.c
+++ b/mm/bootmem.c
@@ -234,6 +234,9 @@ static void __init __free(bootmem_data_t
sidx + PFN_DOWN(bdata->node_boot_start),
eidx + PFN_DOWN(bdata->node_boot_start));

+ if (bdata->last_success > sidx)
+ bdata->last_success = sidx;
+
for (idx = sidx; idx < eidx; idx++)
if (!test_and_clear_bit(idx, bdata->node_bootmem_map))
BUG();
@@ -263,40 +266,57 @@ static int __init __reserve(bootmem_data
return 0;
}

-static void __init free_bootmem_core(bootmem_data_t *bdata, unsigned long addr,
- unsigned long size)
+static int __init mark_bootmem_node(bootmem_data_t *bdata,
+ unsigned long start, unsigned long end,
+ int reserve, int flags)
{
unsigned long sidx, eidx;
- unsigned long i;

- BUG_ON(!size);
+ bdebug("nid=%d start=%lx end=%lx reserve=%d flags=%x\n",
+ bdata - bootmem_node_data, start, end, reserve, flags);

- /* out range */
- if (addr + size < bdata->node_boot_start ||
- PFN_DOWN(addr) > bdata->node_low_pfn)
- return;
- /*
- * round down end of usable mem, partially free pages are
- * considered reserved.
- */
+ BUG_ON(start < PFN_DOWN(bdata->node_boot_start));
+ BUG_ON(end > bdata->node_low_pfn);

- if (addr >= bdata->node_boot_start &&
- PFN_DOWN(addr - bdata->node_boot_start) < bdata->last_success)
- bdata->last_success = PFN_DOWN(addr - bdata->node_boot_start);
+ sidx = start - PFN_DOWN(bdata->node_boot_start);
+ eidx = end - PFN_DOWN(bdata->node_boot_start);

- /*
- * Round up to index to the range.
- */
- if (PFN_UP(addr) > PFN_DOWN(bdata->node_boot_start))
- sidx = PFN_UP(addr) - PFN_DOWN(bdata->node_boot_start);
+ if (reserve)
+ return __reserve(bdata, sidx, eidx, flags);
else
- sidx = 0;
+ __free(bdata, sidx, eidx);
+ return 0;
+}
+
+static int __init mark_bootmem(unsigned long start, unsigned long end,
+ int reserve, int flags)
+{
+ unsigned long pos;
+ bootmem_data_t *bdata;
+
+ pos = start;
+ list_for_each_entry(bdata, &bdata_list, list) {
+ int err;
+ unsigned long max;
+
+ if (pos < PFN_DOWN(bdata->node_boot_start)) {
+ BUG_ON(pos != start);
+ continue;
+ }
+
+ max = min(bdata->node_low_pfn, end);

- eidx = PFN_DOWN(addr + size - bdata->node_boot_start);
- if (eidx > bdata->node_low_pfn - PFN_DOWN(bdata->node_boot_start))
- eidx = bdata->node_low_pfn - PFN_DOWN(bdata->node_boot_start);
+ err = mark_bootmem_node(bdata, pos, max, reserve, flags);
+ if (reserve && err) {
+ mark_bootmem(start, pos, 0, 0);
+ return err;
+ }

- __free(bdata, sidx, eidx);
+ if (max == end)
+ return 0;
+ pos = bdata->node_low_pfn;
+ }
+ BUG();
}

/**
@@ -307,12 +327,17 @@ static void __init free_bootmem_core(boo
*
* Partial pages will be considered reserved and left as they are.
*
- * Only physical pages that actually reside on @pgdat are marked.
+ * The range must reside completely on the specified node.
*/
void __init free_bootmem_node(pg_data_t *pgdat, unsigned long physaddr,
unsigned long size)
{
- free_bootmem_core(pgdat->bdata, physaddr, size);
+ unsigned long start, end;
+
+ start = PFN_UP(physaddr);
+ end = PFN_DOWN(physaddr + size);
+
+ mark_bootmem_node(pgdat->bdata, start, end, 0, 0);
}

/**
@@ -322,83 +347,16 @@ void __init free_bootmem_node(pg_data_t
*
* Partial pages will be considered reserved and left as they are.
*
- * All physical pages within the range are marked, no matter what
- * node they reside on.
+ * The range must be contiguous but may span node boundaries.
*/
void __init free_bootmem(unsigned long addr, unsigned long size)
{
- bootmem_data_t *bdata;
- list_for_each_entry(bdata, &bdata_list, list)
- free_bootmem_core(bdata, addr, size);
-}
-
-/*
- * Marks a particular physical memory range as unallocatable. Usable RAM
- * might be used for boot-time allocations - or it might get added
- * to the free page pool later on.
- */
-static int __init can_reserve_bootmem_core(bootmem_data_t *bdata,
- unsigned long addr, unsigned long size, int flags)
-{
- unsigned long sidx, eidx;
- unsigned long i;
-
- BUG_ON(!size);
-
- /* out of range, don't hold other */
- if (addr + size < bdata->node_boot_start ||
- PFN_DOWN(addr) > bdata->node_low_pfn)
- return 0;
-
- /*
- * Round up to index to the range.
- */
- if (addr > bdata->node_boot_start)
- sidx= PFN_DOWN(addr - bdata->node_boot_start);
- else
- sidx = 0;
-
- eidx = PFN_UP(addr + size - bdata->node_boot_start);
- if (eidx > bdata->node_low_pfn - PFN_DOWN(bdata->node_boot_start))
- eidx = bdata->node_low_pfn - PFN_DOWN(bdata->node_boot_start);
-
- for (i = sidx; i < eidx; i++) {
- if (test_bit(i, bdata->node_bootmem_map)) {
- if (flags & BOOTMEM_EXCLUSIVE)
- return -EBUSY;
- }
- }
-
- return 0;
-
-}
-
-static void __init reserve_bootmem_core(bootmem_data_t *bdata,
- unsigned long addr, unsigned long size, int flags)
-{
- unsigned long sidx, eidx;
- unsigned long i;
-
- BUG_ON(!size);
-
- /* out of range */
- if (addr + size < bdata->node_boot_start ||
- PFN_DOWN(addr) > bdata->node_low_pfn)
- return;
-
- /*
- * Round up to index to the range.
- */
- if (addr > bdata->node_boot_start)
- sidx= PFN_DOWN(addr - bdata->node_boot_start);
- else
- sidx = 0;
+ unsigned long start, end;

- eidx = PFN_UP(addr + size - bdata->node_boot_start);
- if (eidx > bdata->node_low_pfn - PFN_DOWN(bdata->node_boot_start))
- eidx = bdata->node_low_pfn - PFN_DOWN(bdata->node_boot_start);
+ start = PFN_UP(addr);
+ end = PFN_DOWN(addr + size);

- return __reserve(bdata, sidx, eidx, flags);
+ mark_bootmem(start, end, 0, 0);
}

/**
@@ -410,17 +368,17 @@ static void __init reserve_bootmem_core(
*
* Partial pages will be reserved.
*
- * Only physical pages that actually reside on @pgdat are marked.
+ * The range must reside completely on the specified node.
*/
-void __init reserve_bootmem_node(pg_data_t *pgdat, unsigned long physaddr,
+int __init reserve_bootmem_node(pg_data_t *pgdat, unsigned long physaddr,
unsigned long size, int flags)
{
- int ret;
+ unsigned long start, end;

- ret = can_reserve_bootmem_core(pgdat->bdata, physaddr, size, flags);
- if (ret < 0)
- return;
- reserve_bootmem_core(pgdat->bdata, physaddr, size, flags);
+ start = PFN_DOWN(physaddr);
+ end = PFN_UP(physaddr + size);
+
+ return mark_bootmem_node(pgdat->bdata, start, end, 1, flags);
}

#ifndef CONFIG_HAVE_ARCH_BOOTMEM_NODE
@@ -432,24 +390,17 @@ void __init reserve_bootmem_node(pg_data
*
* Partial pages will be reserved.
*
- * All physical pages within the range are marked, no matter what
- * node they reside on.
+ * The range must be contiguous but may span node boundaries.
*/
int __init reserve_bootmem(unsigned long addr, unsigned long size,
int flags)
{
- bootmem_data_t *bdata;
- int ret;
+ unsigned long start, end;

- list_for_each_entry(bdata, &bdata_list, list) {
- ret = can_reserve_bootmem_core(bdata, addr, size, flags);
- if (ret < 0)
- return ret;
- }
- list_for_each_entry(bdata, &bdata_list, list)
- reserve_bootmem_core(bdata, addr, size, flags);
+ start = PFN_DOWN(addr);
+ end = PFN_UP(addr + size);

- return 0;
+ return mark_bootmem(start, end, 1, flags);
}
#endif /* !CONFIG_HAVE_ARCH_BOOTMEM_NODE */

@@ -721,7 +672,7 @@ void * __init alloc_bootmem_section(unsi
if (start_nr != section_nr || end_nr != section_nr) {
printk(KERN_WARNING "alloc_bootmem failed on section %ld.\n",
section_nr);
- free_bootmem_core(pgdat->bdata, __pa(ptr), size);
+ free_bootmem_node(pgdat, __pa(ptr), size);
ptr = NULL;
}

--- a/include/linux/bootmem.h
+++ b/include/linux/bootmem.h
@@ -66,7 +66,7 @@ extern void free_bootmem(unsigned long a
#define BOOTMEM_DEFAULT 0
#define BOOTMEM_EXCLUSIVE (1<<0)

-extern void reserve_bootmem_node(pg_data_t *pgdat,
+extern int reserve_bootmem_node(pg_data_t *pgdat,
unsigned long physaddr,
unsigned long size,
int flags);

--